Train signaling system



Nov. 22,1932. H, A. THOMPSON TRAIN SIGNALING SYQTEM Filed Jan. 6, 1952 5 Sheets-Sheet l .7720/22ps'0fi.

M6 ATTORNEY Nov. 22,1 1932. .H. A. THOMPSON TRAIN SIGNALING SYSTEM 3 Sheets-Sheet 2 r r MW INVENTOR HawardAJhompsazz.

QJLW HIS ATTORNEY Filed Jan. 6, 1932 Nov, 22, 1932. H. A. THOMPSON 1,883,706

- TRAIN SIGNALING SYSTEM Filed Jan. 6, "1952 s Sheets-Sheet 3 INVENTOR HowardA. 7710112123012.

BY QKM HIS ATTORNEY UNITED} STATES I Patented Noy. 22, 1932 HOWARD .A. THoMrso v, or EnGEWoon, rEnNsYLvAnIA, .Assienon'ro Innun on swrron & SIGNAL COMIANY, or swIssvsLE, PENNSYLVANIA, "A. CORIORATIONOE PENNSYLVANIA rimiiv sIenALIne sys'rnn l Application filed J'anuary G, Serial No. 535,044. f

Mypresent invention relates to a trainsig-V naling system for operation of block signals or the like arranged to display different signals to trains travelling at different'speeds to the end that slow speed trains may be per mitted to run closer together than trains operating at higher speeds. In accordance with the invention, a train of higher speed overtaking-o'ne travelling at a lower speed, will be obliged to reduce its speed to or below that of the first'train in order to receive a proceed signal, and, if the approaching train is trav elling at a high rate of speed, it 'will're'ceive a restrictive signal a greater number of blocks behind the leading train than would'a train approaching at a low rate of speed. i

The present invention maybe applied, for

1 example, to insure thata train running at sixty miles per hour, or more, shall receive a caution indlcatlon unless there are at least six blocks'clear ahead of it, that a train run-.

ning between fifty and sixty miles per hour shall receive a caution signal unless there are at least five blocks clear ahead of it, a train running between forty and fiftymilesper hour shall receive a caution signal unless there are at least four blocks clear ahead of it, and so on; the slowest trains receiving a caution signal when only one clear block is ahead.

reference maybe had to the accompanying drawings, of which Fig. 1 illustrates diagrammatically a signaling circuit adapted to differentiate between trains running at six different speeds and utilizing time element re laysfor selectively operating the track signal in accordance with the speed fot the ap proaching train and'the number of cl'ear blocks ahead. Fig. 2 illustratesjdiagrammati cally a circ'uitsimilar"tothat of Fig.1 but utilizing in place of the time element relays thereof a single automatically wound time release ateachsignal having aplurality'of con and relay. 8TB with block 8'.

tacts adjusted for-closure.after'diiferent periods of time. Fig- 3 illustrates diagrammatically another circuit of the type of Fig. 1

but utilizing a plurality of glow discharge tube circuits and relayswhose timesof pick up are controlled thereby 'inpl'ace ofthe time element relays of Fig. 1. Figt'illustratesdi- 1 agrammatically an alternative arrangement utilizing 7 slow pick-up] relays and additional series track "relaysfi Fig. illustrates dia grammatically another circuit of thetypeof Fig.4 but utilizing slow release relays in place of-the slow pick-up relays of Fig.

; In Fig. L the track It is shown as divided a signal indicated diagrammatically atthe intoeight sections 1, 2',3, 4,'5 ,6, 7 and 8 with entrance to -each block, the signal at the entrance to block l being identified by the ref- 'erence character 18, that atthe'entrancej'to block 2 by 2S, and so forth." *Block 8 isshown asoccupiedby atrain'T, which, for convenience may be conside'red as-satisfactory. A

track battery 1E for blocl'c 1' supplies current for the track relay lT-B which is connected across-the rails R in the usual manner to be :short' circuited when the blockis occupied) Similarly, battery QEand track relay 2TB.

are associated with block 2, battery 3E and track relay 3TB with block 3, batterylE and.

track relay 4TB with block Q-battery 5E and track relay 5TB withblock'5, battery G'E and track relay 6TB with block 6, battery 7 Eand -m'ent illustrated, is to respond to six difi'erent zones of train speed, seven relays are asso track relay 7TB with block '7, andbattery l ciated with the control'ofieach signal. These seven relays at signal 2 comprise a relayQDR normally energized whenat least six blocks in advance are clear; five time o element relays, ZTE-l, 2TE 2, I 2TE 3,; 2TE+4 I and 2TE-+5 normally deenergi'zed but adaptedto be energized as a train approaches the signal; and an auxiliary relay 2TS which isuse'd to insure that the time elementdevices 2TE,Q1,

QTE- Q etc. assume their fullnormal posi tions' when deenergized'. When-relay 'QDRI'is energized, battery, the positive terminal: of,

which is 'indicatedby the reference-letter i over front-contacts are energized,relay 2DR as will bet-energized anda train in blockl will for example, energized and held energized long enough for the time controlled armature thereof to be raised, the :circuit for therpro ceed indication of signal is maintained over. a back .contiact'of reIayQDR" and a front contact ofi'time relay 2TE-5. "If" time relay 2TE 5 is deenergize'd and time relay 2TE4 energized and has closed its'top con- I ttacts,the circuit for the proceed'indicationof signal2S is maintained over backcontacts' of I relays 2BR and 2TE-V ,5 and front contact of relay.2TEfl. IQ a Similarly, atsignal 3S, the circuit for' the clear indication is from battery overfla top contact-of relay 3TR, -a-.top contact of relay 3T3v and atop vcontactofrelay-3Dh if this relay is energized ;i. or over a back contact thereof when deenergized and atop contact of V thehighest numb red time element relay at that signal th'at hasclosed its top contacts,

and. over backcontacts' of higher numbered relays, iii-any,- at that signal; 5

The circuit'for relay QDR for convenience has been shown in heavy lines and is asfolt B Y; over-front contacts of track relays 7TB, 6TB, 5TB, 4TB, 3TR and 2TB, winding of "relayQDR to jcommon. =As all track relays-i controlling the above circuit receive a, proce'edior 'clearsignal'at the env 2TB causing common to be connected over a;

trance to block2, relay QTS being energized as hereinafter. described .in connection with the correspondingrelay at signal 38. As the train enters block 2 it will shunt track relay backcontactf of this relay to the windings of alltimeelement relays atsignalf3. As a trainis in block 8 the circuit of relay 3DR will be open over a front contact of track relay STR, 'All time element relays at signal 3 :will-become energized by the connection of common over the backcontact oftrack relay 2TB, battery being supplied to time element relay 3TE-"j-5 over the circuit traced for re- 7 lay QDR and to the other time element relays at signal 3gby similar circuits including top contacts oftrackrelays of progressively few:

er blocks in advance of signal 3 S The closure of the'circuits of the time element relays at s1gnal1'3 causes the back checking contacts of-these relays to.openimm'ediatelywith con 'se quent'opening of a previously closed picku'p'cir'cuit for re1ay'3TS-,'as the circuit for re lay 3TS is controlledover 'back checking contacts of time elementrelays 3TE-g-5, 3TE-'4, 3TE-8, ,3TEf '2and' 3TE- -l.- ,Rel'ayi3 T does not release, however, because: an ial'ter V native. circuit'thereforfis closed when the train 'sh unts track reI'ay QTR, this alternative circuit being from common over a back contact 2TB, and a top contact of relay 3TS through the winding of the relay'to battery. The time element of relay 3TE-.5 is so adjusted that the time controlled armature of this: relay will be-picked up only if the speed of an approaching train throughout block 2 is less than sixty milescper hour. The time element of relay 3TE4 is so adjusted that the time controlled 'arinature of this relay Will pick up before a train travelling'at less than fifty miles per hour through block 2 reaches signal 38. Similarly, the time ele- 'ments of relays STE-+3, 3TE-2 and 3TE1 are adjusted so that the armatures thereof will be picked up before trains travelling at less than 40, 30 and 20 miles perhourfre spectively reach signal 3SQ Thus,if-,the train approaching signal is travelling at miles per hour, or faster, none of the: time be displayed at signal; 3S, batterybeing supplied to the cautionor yellow lightfof' signal 3S over a front'contactoftrackrelayBTR,

as f eleinent relays offsignalBS will have had 7 timeto pick up their "time contr'olled a,lfirlik. t tures and, consequently, a caution signal. will a front contact of relays 3TS, bafckcontact of relay 3DR and back contacts of all time element relays at this signal. :If the train istravelling at'less than 60 miles per" hour, relay 3TE.5 will have picked up itstime controlled armature between the, tiinegthattrack relay 2TB closed its back contact 7 and the train reached signal 3S'With the result that a: clear s gnal will be given, battery be; ing supplied tothe signal-over top contacts of relays 3TB and 3Tb, a back contact of relay 3DR' and afront contact of tim'e'elenient relay 3TE5. v

- If the advance trainhad been in-block instead of ,block- 8, the circuit for relay 3TE5 Would be openover the front contact of track relay 7TB and-,the approaching train-,- if run ning-between50 and 60 mi les per hour,'would have received-a caution, in-

stead of a proceed signal at signal- ;A train runningat less than50 miles per hour llO would receive a clear signal as the circuit for time element relay 3TE-4 would The closed and the time controlled varmature thereof would be raised to'supply battery to signal 3S to hold it in .clear position; the circuitbeingoVer back contac'ts ofrelay 3DR and of time element relay STE- 5 and front contact of-time element relay3TE ,4c. Similarly, with the advance train in block 6,a

train approaching signal 3, in order to re- 7 less than lO miles per hour inorder to {give sufiicient time for time-element relay 3TE 3 ceive a proceed signal, must be travelling at r to have pickedfup its time controlled arma-fiture and, if the advance train were in'block 5, o'r i, speeds of lessithan 30and 2Omiles if l per hour-respectively arev'required for the succeeding train ,.to 7 receive va" 3 proceed- ,sig

nal. "A train at any speed receives a stop signal at signal 3S-it the advance train is in block 3, battery being supplied over a back contactoftrack relay 3TB. to the stop or red light of signal 3S and the circuits of all time element relays being open over top'contacts of relay 3TB.

Also, it all time element relays at signal 3 had not been in their full normal position at the time the train entered track circuit 2, relay 3T8 would have been deenergized' and the closing of the back contact of relay 2TB could not have energized relay 3TS. A- caution signal would therefore have been dis played being connected over front contact of relay 3TB and a backcontact of relay 3TS.

It will be understood that the time controlled armature of each of the time element relays do not open their back contacts and" close their top contacts until afterthepar ticular period of time for which the relayis adjusted whereas the checking armatures of these relays open 'their; backcontacts immediately upon energization of the relays. No

is intended as the time controlled armature and the lower armature of each pairas that controlling the checking contacts.

:The aboveedescribed system thus;displays signals tending to maintain trains travelling at 60'imilesan hour at-least six blocks apart,

those travelling between 5-0 and 60 miles per s I hour five blocks apart, those between 40 and miles per hour four blocks apart, those between 30-and 40, three blocks apart, those between 20, and 30,'two blocks apart, andthose at'less than 20, one block apart. It the leading train is travelling atyfor example, 40 miles per hour, a train approachinglat miles an hourwould receive'ia caution signal upon entering the block five blocks in the rear'of that occupied and, it it maintained its speed,would continue to receive a. caution indication at the entrance to each block until it receiveda stop signal asit approached the occupied block unless it reduced its speed to that of preceding train, assumedto be 40 miles per hour and malntalne'd four clear blocks betweenit an dtheadvance train. If

speed zones, but obviously the system lends itself to. expansion. or contraction of. the number of zones as desired. The circuit of. Fig. 2 difiers from that of Fig. l primarily in that the time element relays ateach signal are replaced an automatically wound time release device having a plurality of differently timed contacts-corresponding in function tothe time controlled armatures of the time element relays of Fig. 1, and in that a separate'relay, indicated by the reference letters HD with a different numeral prefixed according to the signal with which it is associated, is provided to directly control the signal. only is illustrated to avoid repetition at each signal of substantially identical apparatus and circuits. The' time release devicei controlling ignal 28 is indicated diagrammatt" cally at QTD' as includingfa motorM, slot Winding SW and thre P l fof slot .contatss In Fig. 2 the circuit at. signal 2S" SCI, S02 and 8C3, the first pair'ofwh-i ch, '7

is opened when, and only when, the time re} lease is. fully. wound, and the; second. and

third pair of whichare closed when "an'd only *QTD- l and 2TD.5 after varying timein-f tervals; The release of deyice*"2TD occurs opened and, as this circuit is controlled over when the time'release is Itullywound. flDee atop contactof track relay lTR- andflslot'.

. contacts SG3, it follows thatfthe approach of a train into block 1 causes release of 2TD- with consequent successive closure of the top, contacts of arms 2TD-r-5, 2TD4, etc. Arm 2TD,1 is arrangedlto close its top contact.

so slowly that, in order .for it to be closed before a train reaches signal 2S,the train must have been travelling through block 1 at .lessthan 20 miles per hour: Arm 2TD-2' is arrangedto close its top contact'betore a" train travelling at 30 miles per hour reaches signal 2S, and arms 2TD .-3. 2TD-4and '2TD '5 are similarly arranged to close: their top contacts-before a traintravellingthrough to indicate'onthe drawings the actualmch anisms controlling themovement of arms 2TD 1,"2TD2 etc. These arms. control a relay QHD which in turn controls signal 28 aslhereinafter described. V

' The circuit of the proceed i'ndication for signal 2S isover a top contact of trackf'relay l i 2TB; a top contact of a relay 2P anf d 'a'top contactot relay 2H1) 1 One endloff the winding of relay 2Pis conj nectedto comumon and the, other end of the winding is normally connected'tofbatter-y I over slot contacts SC The 'circuitiorthe caution indicationfor signal 2S is overa top contact of relay 2TB and a back contactof relay-2P-or over top contacts of relays 2TB i Fig. 1'. This normal circuit for relay 21-11) ber of signals,

is over top contacts of track relays six blocks in advance of signal QS and over back contactsofsuccessively higher numbered contact 7 arms of the time release devices at the five signals immediately in advance of signal 2S.- "There are five other alternate circuits for relay'QHD each including a top contact of one of 'the arms 2TD1, 2TD2, etc. The

circuit including the top contact of. arm

2TD- 1 is over a top contact oftrack relay 2TB; that including the top contact of arm 2T D+2 is over top contactsof the track relaysifassociated with block Q'and the succeeding block and over aback contact of the low- 7 eSt'cOntact-arm associated with the time release "device at signal 3. Similarly, the other alternate circuits for relay QHDfincludejtOp contacts of'a progressively increasingnum-- ber oftrack relays andback contacts of contact'arms at a'progressi'vely lncreasing num- In order to nderstandthe operation of thecircuits of Fig. 2, assume first that there are six unoccupied blocks ahead of signal 2S As a train enters'block 1 it shunts track relay 1TH and thereby opens the circuit 'for slot windin'g'SVV and causes time'r'elease QTDto begin to unwind with consequent successive lifting of arms 2TD'5, QED-4, etc.; and

also closes a circuit, battery overa back contactfof track relay 1TB and a top contact on rela-y QP to the winding of that relay to,

holdit energizedafter the opening of Contact 'SG As six clear blocks were assumed and I consequently relay QHD' already energized,

miles per hourthrough block 1, top contact the first-mentioned iresult is ofno importance at'this time. Assume, however, that but'five blocks ahead of signal 2S were-clear. Then,

beforethe approaching train entered block 1;

relay 2HD was deener'gi-zed over the top con- "5; tact ofthetrack relay six blocks ahead. If

the approaching train travels through block 1 meow-more miles per. hour, then the top contact of arm -2TD5 will nothave had'time to'iclose. before the'train reaches signal 2S and consequently the caution signal will'be displayed; the circuit being, as abovede-i scribed, over a top'contactof relay 21 ,2. back contact of relay QHD and over a'top'contact fof track relayQTR-Q If, however, the approachingtrain is running. at 'less than of a'rm{ 2T D-5 will'clo se, energizing relay ZHDo'ver the longest ofthe above-described alternative circuits." A clear signalwill then 3 bei displayed at signal 28. Ifthe're are but four clear blocks ahead thislongestalternative circuit willbe open over the top contact of the track relay five blocks ahead and the train, in order to-obtaina clear signal, must travel through block lat less than 50 miles per hour in ordertogive time for arm 2TD'4 .to close its top contacts. Similarly, with but three or two clear blocks ahead, the speed of the approaching train must be correspond lngly less 1n orderto obtain a clear signaL If 7 block 2 is occupied, a train-travelling through block 1 at anyspeed will receive a stop signal as the clear; and caution circuits will be opened over the topcontact of relay 2TB and the stopcircuit for the signal closed over the back contact of relay 2TB. i I e I o J When the approachin train clears block 1, trackrelay 1TB becomes energized and opens the stick circuit of relay 21 deenergizingthat.

, The closure oftheitopcontacts of relay 1TB connects battery over, a back contact of relay 219a slot winding SWV and also vover'contact I SC to the motor M causing it to begin to rewind the device. W hen fully wound, slot contacts SC 'open, stopping motor M, and also contacts'SCgclose energizing relay 2P. Bat- V tery is also" connected-over atop contact of relaylTR nd contacts S0 to'windin Syv' V o hold the vice wound. up after opening f the motorcircuit and 'reen'ergization of re If device 2TD relay 2P cannot againbecorne energized and the signal Wlll consequently display a cauis' not completely Woundup,

tionindication. This arrangementfinsuresthat should the motor fail to rewinddevice 2TD, leaving all or a. part :of the .top' con-1 tacts 2TD+5, 2TD 1, etc., closed, the circuits for the proceed 'indication'of signal '2 will be broken over the front contact of relay 2P and hence a' falsel proceed indication will be avoided. -Also when relay 2P, is de-: energized upon vacating the'track circuit, andshould a following train enter the track" circuit, which might easily occur from .a siding switch, before device 2TD is fullywound,

relay 2]? will not become energized." This in? V sures that device 2TD must be fully energized or wound before can bedeenergized to imitate the measurlng of, a time. interval. Cor- .recttlme measurementsunder all conditions is thus assured. i

In Fig. 3, a, signal 51161 01 s stem use glow dischargetubes, condensers and resist ance elements to efiectdifferent'delayiperiods in thepick-up time of a'plurality of relays 5 at each signal is" illustratedlfTherelaysat r each signalcorrespond to the time element relays of Fig.1. These relays, together' with an additional relay whosetime-"ofpickup 'is notaffected flow discharge tube circuits, control a signal controllinglrelayiat each, signal corresponding to the relayflso' of'Fig. 2. As in Fig. 2 the circuit. at butone signal is illustrated for'convenien'ce.

In Fig. 3 the signal indication circuits-for signalQS aregsubstantiallythe same as in 5 Fig. 2. 'The circuit-for the proceedin'dica- .tion is over top contacts OitIELOkI'BlELYQTR' and of relay .QHD thatfor "the cautionindication over top contact of'relay 2TB and back contact of relay'2HD and that forthe stop indication over, back contact of relayQTB.

.:When there are six clearbloclzs aheadyof signal 2S, a relay 2D.+6 controls the ci'rcuit' lays at each of the fiye IIBXtQSlgIlEtlSQhThG five; alternative circuits for relay 2H1) are also just as in Fig. 2 except, ofcourse, that ries with the Winding ofrelay 2D 1 is a resistance 2Rj1, a glow discharge tube 2N- 1 and a continuity'transfer contact of thatre lithegwinding of therelay, continuity transfer contact: and glow discharge tube2N1".' Battery is supplied to this circuit, preferably from a source of 110 volts D. C. ,over'a top contactof relay 2D 6, when the latter is energized; common being. connected to the other side of the inding of relay, 2D-1 'When relay 213 -1 .picks up its .armatures, due to the closureof the above-described cir- .sc cuit at the top contact of relay 2])9-6, the

' fifth alternative circuit for relay is completed and astickcircuit for relay 2D5 -1 is closed, disconnecting elements 2R 1 and QN-l. "The continuitytransfer contact in- 1 sures closure of the circuitthrough these ele ments until after closure ofthe stick circuit. "Similarly, elements, 2R.2, x 2 pand 2N2 are associated: ith" relay 2D- 2," 'controlling the fourth alternative circuit for relay QHD, and are disconnected whenthe stick circuit for. relay 2D2 is; closed. .Corre ,sp ondingly identified elements 3 are associated When. a train. enters block 1 it deenergizes traclr relay 1TB and thereby causes relay for relay. 2D6. being from battery ovena back contact of relay l'IR- Theiclosureof the top contacts closes the. above described pick up circuits, of relays 2l l,. f2, lg) 2, ,2Df3, 2D..4 and 2D.5, causing these ,re-

lays to pick up their armatures after periods of time depending upon the jparticular re sistance,' capacity and glow discharge tube el me ts ass atesl t er with me ts back contacts of the'relays at each'signal are substituted for hackgcontacts of the time-relay. A capacity 20 .4 is connectedacross there are but five'ifunoccupied ,.blocks;- lthe Similarly, with butthree, twoand oneiunocis partially approachcontrolled; thata is, in

ig; 3 a cautionindication is normall ydis' played-at each signal. As the timing-devices whichare subject to failure it isnot necessary to provide the checking features of Fig 2D6 to pickup its armatures, the-circuit 2N'1, 2R+1 and are so chosen as to cause-relay2D+l to close its top'contacts before a train 'travellingat lessthanQO miles per hour through block 1 reaches signal2S. E1ements 2N- L2, and 2C. j2, are so chosenas to cause relayQD-Q to close its top" contacts before a train travelling at less than 80 miles .per hourjthroughblock; l reac'hes. signal 2S. Similarly, the elements associated with relays 2D3,' and 2D ,''5 aregso chosen as to cause these relaystoclosethe'ir top contacts before trains' travelling aimless than 40, .50 and miles perh'our respectively" 5' nected to common over a back contact ofg-re'j f lay 2D-;.6 Whenthat relay is fdeenergized to I 3 I insure that the condensers are' ifuHyfdi'scharged each time'the traclrcircuitisyacated to'insure accurate' timing. I

The'control "signalQSJin with the numberT of unoccupied blocksinsad} Y "yanceofsignal 2S and With'the speed of the i approaching train will be clear from the description already given in fconnectionflwith Figs. 1' and 2. If there aresix or. more um occupied blocks; relay; 2HD "is energized, :ir respectiye of thei'speed'of the approaching- I train, over a top contactfofrelay 2D+.6;L: If 3 speed of. the trainmustbedessthan 60 miles:

1 per hour in order to cause'closureof-the first alternative circuit of relay .2HD, theinormal circuit'therefor being 'brbkenorer a to'pcone tactof the track relay six blocks'aheadof the train, to receive a clear, signal, must travfel through block 1 at less-than 50iniles per hour;

cupied blocks, the approachingatrain must travelatless than. .40, 30 andQOJ miles per hour, respectively, in orderto receive a ..pro,'-r 'ceed rather than a; cautlon lIldlCEttlOIlz ;Unli ke the circuit ,of Fig. 2, that vof Fig.5?

of Fig. 3 'd() not 'involvemechanical Erparts and2." a V In Figs. 4 was alternativesystelns o ffthfe same type .but utilizing relatively cheaper relays a're substituted for the time element relays of Fig. 1, thetime release device'sjof '1 "Fig. 2 andthe glow. discharge tubecircuits' of Fig.3. The use of such relatiyelygcheaper relaysrequires an additional seriesjitrackre lay for each block, which additionalfrelays l signal. If there are-but four clear: blocks, the first alternative circuit. is open 'andthe,

Slow pick'up (Figrs1ow release (Fig- 5) I As in FigsJQ and 3,- theci-rcuits of Figs-.4: as

'5 :are illustrated for signalQS only.

In Fig, 4 relay 2DR corresponds in func- I =tion to the similarly identifiedrelay of Fig.

I contactsythe circuit for the proceed indicationq is closed over a' back contact of relay- 2DR, top contact of the highest numbered-relaywhich has raised its armat'ures andback contactsjof higher numbered relays if an i Y j If the'armatures of all relays at signalQS are 'jdo'wn and-block 2 unoccupied, the circuit for '-back'contacts offall' DR relays, and" if relay:

2TR:is shunted, the circuit for the danger indication of fsig'nalfZS is closed overa back the caution indication of signal' 28 is closed overa top contact of' track relay 2TH] and contact of thisrelay. I

Relay 2BR is normally energized over a -Ecircuit-like that indicated in heavy lines for "this relay in- Eignlibut including also top contacts ofallofthe ATR relays in the six blocks'in advance of the signal and including s also, for-checking purposes, a back contact ofrelay-2D 5-and back contact of progtes: sivelylower numbered relays at the four sig- ,nals' in advance of signal 2S. Common is connected over a back contact of track relay 1TB and a top contact of series track relay 'AlTR to one side of the windings of each of :the .slow zpick-up relays QDR l, 2DR-2,

ing normally connected to the other sides of these relays over circuits similarto that of relayQDR but including contacts of relays at p progressively fewer'blocks and signals in advanceof si'gnal'QIS. Relay 2DR'5 when energized long 'enough for its armatures to bev raised, is held energized by a stick circuit over its own armature", common "being: connected to. a topfc'ontactq Similar. stick circuits? are provided for each'; of relays j 2DR,4=, .2DR-3,; 2DR+2 and it will pick up its armatures and close its stick circuit between the closing of the hack 7 fcontactsof track relayv 1TB and the opening of the top' contacts of relay A lTRvcaused by a train travelling through the first or timing section of block 1 at a rate less than miles "per hour. Revenu -4 W111 ick up its armature to close'its stick circuitif the'ap- "proaching train is running at less than. 50' [miles per hour in the timing section,frelay 2DR '3 willpick' up its armature iftheapproaching train isrunning at less'than 4O 1 miles per hour," relay QDR-fZwill pick up Q its armature if the approaching train is runnection with Fi I assume ning at lessi than miles perjhounand relay 2DR1 if thetrain is runningat less thanJQO miles per-hour} I Theoperation of the-circuits of Fig.4is so similar to, that already' 'described incontion thereof would be superfluous.

. gXLtha-t a fse'parate descr p- In Fig. 5 -the slow-release relays for signal ;2SR -2 and 2511 -1, ,-Anadditional relay. 2DR'6 corresponding in partto relay 2D 6 of Fig.3'except that it'is normally energized irrespective of the number of clear blocks ahead c'ontrols'alstick circuit for relay 2HD. :Re1ay;2DR?6 and'the SRfrcla-ys areal-l no! mally energized ever-a top contact of track j'relay lT-R, the circuit'for 'relays 2DR6,

"2SR1 being fthrough-the windings of these relays to j common.

. Thereleaseof eaeh ofthe sntelay at Sig- QS -is initiated upo thefopening of they top contact of relayITR'due toa train travelling through'block 1.3 1

aeiay" QHD is norma ly energized "circuit similar tothat traced forrelay of Fig. 1', but'incluldin'g also the front contacts of the series track relays in eachof the front contact ofseries track relay AlTR.

six" track sections, in advance of signal 23 v and'for checking purposes a front contact of one of theslow releaserelaysatfeachof the" 'fivesignallocations in advance of signal 2S." The circuit for relayQHD continues through the winding of that relay to" common over a An auxiliary stick circuit connection from -the windingv of relay 2HD to common is made over a frontcontact ofrelay 2111) and a back contact of relay 2DR' 6'which relay is deenergized uponfldeenergiz ation of relay l'IR whenva train enters track circuit '1. Under normal trafficconditions this auxiliary stick circuit is-cl o'se d *beforefthe o en; 7 ing of theffirst connection tocommon over the front contact of relay'l AlTR.

If less'than six tracksfections in advance J nativ'e' circuits'may energize reIa'yQHDL, If,

for example, fivetrack' sections invadvance' V offsignal 2Srare'lclear andif the approachlng train isjtravelling less than. 60: miles per hour, relay SR" "5 WilIEhave closed its back contact 'beforegthe opening of the front con tact 'off relay-AlTR-g This connects the first falter-native circuit which includes the front contacts ofthe track relaysof five track sec- V ]tions' in, advancaiover a jback contact of re-.

lay 2SR 5, then the winding ofrelay 2HD to commonbver a. front contact of-relay A1TR.; The stick circuit connection tojcomm -n', formerly'traced, will be closed immedif ately up'on energization of relay QHD, so that a proceed indication will; be displayed by.

signalZS under these conditions. ""If the ape I -proaching train- 1 is exceeding 60 miles f per 7 narytrack relays Inasmuch as theord1- "metros hour, Irelay AlTR will have-opened its front contact before relay 2SR5 closes itsback contact; The pick-up circuit is thereforenot closed and'rela'y QHD remains deenergized causing a caution indication to be displayed.

The second, third, etc. alternative circuits are similarly available to energize relay QHD over back contacts of relays QSR-A, 2SR 3, etc. The timing of the speed of trains, as in Fig. 4, is thus measured between the deener= In each ofFig s. 4 and; 5the alternative circuits for'controlling the proceed indication of the signals havebeen shown anddescribed ascontrolled over top contacts of the series track relays as well as over the ordinary track relay of" any block will drop its armatures if any portion of that'block is occupied and the series track relay will only drop its armatures if the latter portionof the block is occupied, it is apparent that-the control' of these alternative circuits overthe top contacts of the'series track relays isinot essential. Such control is advisable, however,

as a safetyfeature, for itprovides a check upon the condition oftheseries track relays. Itwill be apparent that the speed of trains may be timed at or near the exit end of each block in Figs. 4 and 5 by the use. of a'n additional series track relay. p

The invention has now been describedin connection with five embodiments thereof. In all embodiments, for ease of comparison, the same number of speed Zones and the same speed limits therefor were assumed but it will be readily appreciated that in any actual installation the particular number "of zones,- and the particular limits thereof, would besele'cted by the railroad oiiicials,

the circuitsof'the invention lending them-- selves'readily to modification in this resnect. Also, in each embodiment of the invention no maximum speed limit was assumed when there were six clear blocks ahead of a signal. If such a maximum limit were desired, only slight'modific'atio'ns of the various circuits would be required. in Fig. -1, forexainple, a time element relay having the proper period of pick-up would be substituted for each DR relay; In Fig. 2 the normal 'circuit of eachHD relay would be'carried over afront contact of an additional contact arm of the time releasedevice. In Fig. 3 an addi-,

4 the DR'relay would be made slow in picking-fup' and in Fig. 5 an additional slo'w release relay would be provided to control relay 2H1). Only slihtmodification would blocks, g V embodiment could be combined with features a be required to make the signal of each of the embodiments approach controlled asf'in Fig. 3. If'semaphores instead of the indicated lights are to be employed, no change in the circuits is required andthe circuits for the danger indications could be omittedi i a If but two indication signals rather than three indication signals were desired, thecir- "cuit, in each embodiment described as c ntrolling the caution indication could be-em ployed tocontrol the danger indication instead of the caution indication; the circuit",

described for the danger indication being also retained if desired, or battery being permanently connected to a back contactof the slowest'ac ting relay or contact arm with consequent"discontinuation of the" control or? l the dangerindica'tionover back contacts of; I V

the track 'relays. Also a separate iaspectasuch as yellow over green might be displayed in-v stead of green when less than six bio'clrsare clear if the train is. proceeding atreduced speed inproportiontothe numberQof clea-r Obviously, .-.niany features of one v of another embodimentand various elements it could be omitted or modified without departing'from'the spiritof the invention;

Thefollowing is claimed:

1. A railway blocl csignaling system comprising in combination, alsignal at the en trance to eachblock adapted tofgive aapro ceed indication and at least'one'other more restrictive indication, aiplu'ralityvofPaiternativecontrolsfor each signal responsive to track conditions over a difiterent number i of blocks in advance of thesignal,andalne'ans responsivefto the ratel at which a train approaches'a signal for selecting which of said alternative controls will be eliective to operate the. signal; the selectionbeing suchthat a train travelling at anyspeed'will receive "a proceed indication if a number of blocks proportional. to. the: speed of train ung occupied ahead'of the signal, whereinsaid llO signals are adapted. to give three ind'ications lected by said speed responsive means to causethe signal to a proceed indi- CELtlOIYWhGIl the required number ofrbloclrs' -inadvance of the signal are unoccupiedfand corresponding to proceed, caution and stop" 7 and wherein each of "saidalternative con;- trols for each signal is adapted when ssat: the entrance to each bloclradapted to give a proceed indication-and at-leastsone other smorerestrictive indication, a plurality-lofalternative controls for the proceed indication, each'of said controls requirlng a different number of unoccupied blocks in advance of the signal, means initiated bythe approach of a train and responsive to the speed thereof for selecting which ofsaid controls 1s to be activelin controlling the signal, said last mentioned-'means selecting for fast movlng trains controls requiring the greater number of'unoccupicd blocks in advance of the signal,

and-means independent of theispeed of the approaching-train but responsive to track conditions for causing the signal, to display a more restrictive indication under certain conditions, 3 j

3. The combination according-'to claim 2 'wherein said selecting means include a plurality of time element relays each requiring a di'flerent period inwhich to pick up its arn1- 'atures and the. circuits for which are controlled in response to' track conditions over a different number of blocks in advance ofthe signal and are normally opened when no train approaches the signal ;,the relay having the shortest period of pick-up beingcontrolled over the lon'ge'st number of blocks, and so on, whereby. the approach of a train causes completion of all of the circuits of said relays except those which may be open due to trafiic conditions ahead, the alternative con trols being over top contacts of said. time element relays.

4. An automatic railway block'signaling systemcomprising in combination, a signal at the entrance to each block adapted to give a proceed indication and at least one :other more restrictivesignal, a relay associated With'each signal, said relaysbeing adapted to be energized when a' predetermined number ofblocks in advance of the signal associated therewith are unoccupied, a plurality ofiother relays at each signal. each being normally deenergizeid-when the block preceding the signal is unoccupied and each having a different pick-up period for the armatures 7 thereof, that one of said last mentionedrelays having the shortestpick-up period being energized upon the approach of a train to the signal associated therewith if one less than the predeterminednumber "of blocks required for energization of the first mentioned relaysis unoccupied, that one of said last mentioned relays having the next shortest period of pick-up being energized upon the approach of a train if still one less. number of blocks in advance of the signal are unoccupied and the others of said last=mentioned relays being similarly. energized according to theirtime. of pick-upby the approach of a train if progressively less number of'blocks in advance of the signal are unoc cupied, the circuit for said-proceed indication at each signal being closedwheneverthat one of said first mentioned relays is energized or whenvthe same'is deenergized and .top conclosed. 1 i a 8. The combinationaccording to claim 7 tact's of any other one-ofthe relays associated with the same signal are closed and, the :circuit' for a more restrictiveindication at {that signal. being closed when theback con fi s of all of the relays associated therewith are closed. w l r 5, The combination according to claim 14: V

wherein said normally deenergized relays are time element relays and wherein a track relay associated with each block controls overaback contact thecircuits of all ofsaid time element relays ,associatedwith the signal at,

the entrance to the succeeding block, each track relay also. controlling over a top contact the circuit ofthat'one .of saidfrelays pick-up'a-nd associated with the signal at the correspondingly controllingvthe circuits of one oftheothers of said time element relays at progressively preceding signals, v

i 6. :The colnblnatlon accord ng to ilclaim 4 wherein said normally de'energized relays are slowpick-up relays each of which is provided with a stick circuit over'its own top contacts and wherein a track relay and a'series, Y track relay associated with each block control over a back contact of the former and top contact of the latter the circuits of all of said slow pick-up relays associated with the signal .at the entrance to the succeeding block whereby only those relays which have had timeito close 7 7 their top contacts between the closing of the back contact of the preceding track relay and the opening of the top contact of thepreceding series track relay due to the approach of a train toward theassociated 'signalwillremain energized after the series trackf relay of the block preceding the signal has been shunted. 1 a V 7 In an automatic railwayblocksighaling system, the combination comprising a'si'gna'l.

at'the entrance to each block adapted to give a proceed indication and at least one other more restrictive indication, a relay at each signal adapted when energized tovclose the i 5 circuit for the proceed indication at said signal, a plurality of alternative circuits for said relay each controlled in response to trafiic conditions over a different number of blocks in advance of 'thesignal, a plurality of switches associated witheach signal normally maintaining said alternative circuits open, and means respons ve to the approach of a train toward the signal for closing successively after interveningperiods of time first that one of the switches controlling the long est of said circuits, then that controlling the Z next longest circuit, and" so on until. the train reaches the signal or until all switches are wherein a time release mechanism associated with each signal controls said switches, said mechanism including a slot winding normally energized when the block preceding the signal is unoccupied, and deenergized upon the approach of a train, said winding, when energized, preventing the release of vthe the entrance of a train into the block preceding the signal, and each having as an armature the movable member of one of said switches, said relays each having a resistor, a glow discharge tube, and a capacity of such characteristics and so associated therewith as to delay the pick-up thereof and cause the specified successive closure of said switches upon an approach of a train. a

10. The combination according to claim 7, including a plurality of normally energized slow release relays associated with each signal and each having av different release period, that one of said relays having the shortest release period having as an armature the movable member of that one of said switches controlling the longest of said alternative circuits and each of the other of said slow release relays having as an armature, according as the length of period of release, another of said switches, said slow release relays, upon the'approach of a train being all deenergized and, after a period of time varying with the speed of the train, so many thereof as had not released being reenergized to hold open the switches controlled thereby.

11. A railway block signal system comprising in combination, a pluralityof circuits associated with the control oftheproceed indication for each signal, each of said circuits being controlled in response to track conditions over a diflerent number of blocks in ad Vance of the signal, and each being normally open at the signal location when no train is approaching that signal, means initiated by the approach of a train for closing at that signal location first the longest of said circuits and then successively after periods oi time each of the other circuits, any one of said circuits when completed at the signal location and if not interrupted at any other point due to a train in one of the blocks to which it is responsive being adapted to cause the signal to give a proceed indication,

whereby if a train approaches the signal at a rate so great as to have given time for the longest only of said circuits to be closed it can only receive a proceed indication if the greatest number of blocks in advance of the signal are unoccupied whereas, a slower running train permitting a shorter one of said circuits to be closed will receive a proceed indication when there is acorrespondingly fewer number of unoccupied blocks.

12. A railway block signaling system com,- prising in combination, trackrelays for each block, a plurality of relays and a plurality of switches at each signal location, each of said relays having a different operating period and each controlling one of said swltches, a plurality of circuits each adapted when closed to cause the signal to give a proceed indication, each of said circuits being controlled over top contacts of track relays a normally opened at the switch controlled byv that one of said relays which has the shortest period of operation, the next longest circuit being normally open at the switch controlled by that one of said relays which has the next shortest period of operation, and so forth, and means initiated by-the approach of a train for causing successive operation ofsaid relays to close saidswitches after difl'erent periods of timeto successively close first the longest of said circuits, then the next longest, and so forth, whereby the faster moving trains require a greater number of unoccupied blocks in order to receive a proceed indication.

In testimony whereof I aflix my signature.

HOWARD A. THOMPSON. 

